The invention relates to an indexable shell cutter having an improved cartridge for mounting a cutter insert on the cutting face of a shell cutter.
Shell cutters are used to make taps of approximately three inches to twelve inches in diameter into pipe of various sizes and compositions. Such pipes are typically made of cast iron, reinforced concrete, or steel. Shell cutters conventionally are fitted with replaceable cutting teeth of high speed steel or tungsten carbide. One such cutting teeth become worn due to use, either a backup shell cutter must be used or the teeth replaced on the job which results in downtime and increased labor costs.
It is also known to provide tapping machines with cutter teeth that are indexable, i.e., teeth which have more than one cutting edge which can be adjusted to provide a fresh cutting edge when the cutting edge becomes worn. Typical of such devices are those described in U.S. Pat. Nos. 3,643,310; 3,839,772; and 3,405,433. However, the very nature of making a cutting tooth indexable presents problems of accurate alignment of the cutting edge into cutting position and mounting the cutting tooth in a manner satisfactory to absorb the forces imposed perpendicularly on the tooth during the cutting operation.